1. Field of the Invention
This invention relates a rotation anticathode-X ray generating equipment which is capable of generating a X ray having a super high luminance.
2. Description of the Prior Art
A X ray diffraction measurement, etc., often requires the irradiation of a X ray having a maximum intensity for a sample. In this case, conventionally, a rotation anticathode-X ray generating equipment has been used as a X ray generating equipment.
In the rotation anticathode-X ray generating equipment, the X ray is generated by irradiating electron beams for the outer surface of a cylindrical anticathode (target) with rotation in which a cooling solvent flows. Compared with a fixed target type X ray generating equipment in which the target is fixed, the rotation anticathode X ray generating equipment has various irradiation positions of the electron beams with time, so that it can have extremely large cooling efficiency. Therefore, the rotation anticathode-X ray generating equipment can irradiate the electron beams having large currents for the anticathode and thereby, can generate strong intensity (high luminance) X rays.
Generally, the output of the X ray corresponds to the electric power (current x voltage) to be applied between the cathode and the anticathode. Therefore, in exhibiting the output power of the X ray by the electric power, the above conventional rotation anticathode-X ray generating equipment, in which the electron beam having a spot diameter of 0.1xc3x971 mm are irradiated on the target, can have a maximum electric power of 1.2 kW, and even a super high luminance type rotation anticathode-X ray generating equipment can have a maximum electric power of 3.5 kW at best.
This invention is found out in the above background, and has as an object the provision of a rotation anticathode X ray generating equipment which is capable of generating a X ray beyond the limitation of the output in the conventional rotation anticathode-X ray generating equipment.
To iron out the above problem, the first invention is directed to a rotation anticathode-X ray generating equipment comprising a rotation anticathode and a cathode, wherein the electron beam for the anticathode from the cathode is irradiated to the area of the surface of the anticathode on which a centrifugal force acts toward the inner side of the anticathode from the outer side thereof when the anticathode rotates, and thereby, a X ray is generated.
In a preferred embodiment of the rotation anticathode-X ray generating equipment of the present invention, the anticathode comprises a cylinder, and by irradiating the electron beam to the inner side surface of the cylinder, the X ray is generated.
In the above invention, the electron beams are irradiated to the area of the surface of the anticathode on which a centrifugal force acts toward the inner side of the anticathode from the outer side thereof. Therefore, even if the area of the surface of the anticathode is almost melted by the irradiation of the electron beam, it is supported by the structural body inside the anticathode, so that the deformation and the destruction of the anticathode can be effectively inhibited. Consequently, the current of the electron beam to be irradiated can be increased until the temperature of the surface of the anticathode almost reach the melting point of the material constituting the anticathode.
On the contrary, in the conventional rotation anticathode-X ray generating equipment, the centrifugal force due to the rotation acts toward the outer of the anticathode from the area on which the electron beams are irradiated. Therefore, for maintaining the surface shape of the anticathode against the centrifugal force, the surface of the anticathode is required to be maintained at a much lower temperature (about below xc2xd) than the melting point of the material constituting the anticathode. Consequently, the current of the electron beams to be irradiated is restricted so that the surface temperature of the anticathode may not be more than the temperature range.
On the contrary, since the deformation of the anticathode due to the centrifugal force can be remarkably reduced according to the present invention, the surface temperature of the anticathode can be increased up to the temperature near or beyond the melting point, which is 2.5 times or over as high as the conventional temperature range. Therefore, the rotation anticathode-X ray generating equipment can have an allowable loading electric power of 2.5 times or over as large as the maximum allowable loading electric power of the conventional super high luminance type rotation anticathode-X ray generating equipment.